Lighter unit



Oct. 14, 1969 R. s. PIFFATH Ef AL LIGHTER UNIT Filed July 17. 1967 FIGJ INVENTOR RODNEY S. PIFFATH GUSTAV H. NORSTEDT United States Patent a US. Cl. 431-150 7 Claims ABSTRACT OF THE DISCLOSURE A liquid fueled lighter unit in which all of the parts are simply and inexpensively constructed to form an assembly that may be thrown away after the fuel. provided in the unit at the time it is assembled in the factory has been depleted. Fuel primarily in vapor form passes from an orifice in the fuel tank through a passageway filled with cotton to a burner which is ignited by conventional ignition means. The lighter unit utilizes a suction action produced by removal of the cap from the lighter unit to aid in drawing fuel from the tank. To facilitate extended periods of storage of fuel prior to use, the cap for the lighter unit is sealed onto the unit by a band with a pull-off tab.

The present invention relates generally to liquid fueled lighters and more particularly to a small, disposable fighter unit providing improved simplified means for feeding fuel to the burner thereof.

One of the objects of the present invention is to provide a utility-type, disposable lighter unit that can be so inexpensively constructed that the use thereof can compete oostwise with conventional matches, for example.

Another object of the invention is to provide a lighter unit construction that provides the capability of storing and feeding fuel to a burner without valving and within the limits of ignition provided with conventional sparking apparatus.

Another object of the present invention is to provide a fluid lighter unit that operates on fuel primarily in vapor form that passes through an orifice of a tank supplied with liquid fuel, together with novel means for feeding the fuel through the orifice when needed.

Still another object of this invention is to provide a disposable lighter unit construction that enables such a unit initially fueled when constructed at the factory to be stored for an extended period of time under adverse climatic conditions and still be instantly available for reliable operation when needed without requiring any further servicing.

Generally, the economically. formed, disposable, lighter unit of the present invention comprises a plastic molded body forming a tank for holding a supply of liquid fuel; a metallic cup-shaped head supporting a wick-like burner and in ignition means, permanently secured on the upper end of the plastic body; and a removable plastic molded cap for providing a substantially airtight enclosure for the head by tightly fitting over the upper end of the body. When the head is assembled on the upper end of the body, the burner in the head is positioned in one end of a cotton filled passageway which extends through the body so as to be in line with a small orifice provided in the top of the fuel tank. This orifice which is the only opening through which fuel is fed to the burner forms one of the important features of the present invention. The orifice will normally not pass any of the liquid fuel from the tank because of the surface tension of the fluid at the orifice. It is only when the lighter unit is subjected to a shake or jolt that the movement of the fiuid overcomes the surface tension so as to pass through the orifice. However, the orifice, being unobstructed, will at all times pass vapor fuel formed 3,472,599 Patented Oct. 14, 1969 in the space provided in the upper portion of the tank. This vapor form of the fuel is absorbed by and accumulated in the cotton filling which moves the fuel by capillary action through the passageway connecting the tank to the burner.

In the construction of the present invention it has been found advantageous to reduce the orifice in the tank down to a very small size so that the amount of liquid fuel that passes to the passageway when the lighter unit is subjected to sharp uncontrolled movements, as when being carried about in ones pocket for example, is kept sufficiently low so that the burner does not become too saturated with fuel, otherwise the burner will not always ignite. Thus in order to further control the drawing of fuel to assure reliability in the lighter, another feature of the present invention is to provide a more positive means for drawing the fuel through the orifice at the instant the lighter is to be used. This more positive controlling action is provided by the removal of the relatively tight fitted cap which encloses the burner. Thus each time the cap is pulled oif the upper end of the body to get at the sparking wheel to ignite the lighter, a slight vacuum is created in the space above the burner. This action though slight is sufficiently effective to draw a small amount of fuel through the orifice which fuel when added to the vapor fuel already absorbed by the cotton filling in the passageway, assures that the fuel carried to the burner will reliably ignite.

The specific nature of the invention as well as other objects, advantages and features thereof will become apparent from the following description of a preferred embodiment in conjunction with the accompanying drawings in which:

FIG. 1 is a perspective view showing the structural elements of the lighter unit of the present invention;

FIG. 2 is a partially cross-sectional view of the assembled lighter unit shown in FIG. 1;

FIG. 3 is an enlarged cross-sectional view of the head and upper housing portion of the assembled lighter unit shown in FIG. 2; and

FIG. 4 is a perspective view of the assembled lighter unit showing a sealed band and pull-off tab thereon for initial storage.

As shown in FIG. 1 of the drawings, the lighter unit of the present invention comprises a plastic molded cylindrical body 2, the main lower portion of which forms a fuel tank 4. In the preferred construction, the body 2 has a length of about 3% inches and the tank portion is formed with an outside diameter of about A3 of an inch, for example. Integrally formed to extend above the tank 4 is a housing portion 5 of the body 2 having a generally smaller diameter than tank 4. Referring more specifically to the housing portion 5, a recess of a lesser diameter is formed on the upper end 6 thereof and a short ring-like bearing surface or land 7 of a greater diameter is formed thereon a short distance above the top of the tank 4. As will be described later, in connection with FIGS. 2 and 3, the interior of housing portion 5 is also formed with a passageway 14 and an elongated opening 15. The body 2 is made of a polyethylene plastic material that is relatively inexpensive and readily easy to form with the structural shapes described by the use of injection molding. Furthermore, such a plastic material is used since it is both fire resistant and crackproof under conditions to which the lighter of the present invention will be subjected.

The only mechanism provided in the lighter assembly is a metallic head 10 which supports a. burner 12 and a sparking wheel 13. This head is formed as a one-piece die casting preferably composed of a zinc alloy plated with cadmium. The head 10 is cup-shaped such that it can be permanently fitted and secured over the recessed upper end 6 of the housing portion by a press fit such that the outer wall of the head 10 is fairly flush with the outer wall of the housing portion. As noted in the drawings, the top of head 10 is formed with a pair of spaced lugs 17 for pivotally supporting the conventional sparking wheel 13. Notches 18 on the lugs 17 are made slightly smaller than the diameter of pin 19 supporting the Wheel 13 to enable the pin to be pressed thereon for assembly. The head 10 is further formed with two tubular shaped openings 20 and 21 (FIG. 2) extending downwardly from the underside of the head 10 for respectively mating with passageway 14 and opening provided in housing portion 5 of the body 2. A filling 23 of cotton is provided in passageway 14. A spring 24 is positioned in opening 15 for urging a flint 26 (FIG. 3) positioned in tubular opening 21 to bear against wheel 13. A short loop formed from a woven strand of asbestos and cotton is pulled through and extends above the tubular opening in the head 10 to form the wick-like burner 12.

The fuel tank 4 is filled approximately two-thirds of its capacity with a volatile, inflammable fuel such as liquid naphtha-type lighter fuel at the time the lighter is assembled in the factory. The space above the liquid fuel is provided to enable vapor fuel to be formed in the tank. This fuel is preferably provided with an inert coloring agent. The fuel is put into the tank 4 from the bottom end thereof and as shown in FIG. 2 a plastic base member 29 is then fitted into the bottom of the tank 4 and permanently secured thereon by heat sealing. The only outlet from the fuel tank 4 is by way of a small escape hole or orifice 16 which opens into passageway 14. This orifice 16 which is formed in the upper wall of the tank at the time the body 2 is molded is on the order of .015 inch in diameter. Preferably the inside wall 30 of the tank surrounding the orifice has a conically shaped protrusion. The construction of the lighter unit is such that the interior of the fuel tank is at atmospheric pressure. It should be particularly noted that the metallic head 10 by fitting over the end of housing portion 5 provides a heat and fire barrier for the burner 12 preventing the flame from having direct contact with the plastic body 2. This completes the description of body 2 and the metallic head 10 together with the parts mounted thereon.

Next to be described is the removable plastic cap 32 which is made of the same molding material used for the body 2. When the cap is on the lighter unit the inner walls of the cap fit over the housing portion 5 so as to completely enclose the burner 12 and the sparking wheel 13 with the lower end of the cap resting on the top of the tank 4. Furthermore when in this position the lower inner wall of the cap engages land 7 provided on the housing portion 5 thereby providing a substantially airtight enclosure.

It should now be clear that the present invention does not provide any valving mechanism for controlling the flow of fuel from the fuel tank 4 to the burner 12. Nor does the lighter unit of the present invention provide a wick which extends down into the liquid fuel. The orifice 16 is of such a size that even when the lighter unit is held stationary in a tilted position such that the liquid fuel surrounds the orifice, the passage of liquid is resisted due to the surface tension of the fluid. On the other hand, the orifice 16 at all times provides an outlet from the tank for the passage of vapor fuel formed in the space above the liquid, which vapor then accumulates (condenses) on the cotton filling 23 in passageway 14, thereby feeding fuel by capillary action to the burner 12. A slight shake of the lighter unit can cause the liquid fuel to overcome the surface tension at the orifice 16 and to pass through the orifice to charge the cotton filling 23. This manner of passing fuel to the burner 12 can be very effective and in fact occurs in an uncontrolled manner when the lighter unit is carried about in ones pocket.

However, this manner of fuel discharge can overcharge the cotton filling 23 causing the burner 12 to become too wet to give reliable lighting. Accordingly, the construction of the lighter unit of the present invention is considered so as to minimize the amount of fuel discharged in this manner. One of the ways of doing this is by reducing the size of the orifice 16 down to a very small opening, on the order of only .015 inch. Another effective way is provided by the conical wall 30 formed about the orifice 16. As the fuel is moving toward the orifice entrance, the concave shape of the wall 30 surrounding the orifice tends to divert away any fuel not moving directly in line with the orifice.

A positive control for drawing fuel to the burner 12 in the lighter unit is provided by the cap 32 which tightly fits over the housing portion 5 and engages land 7 thereon so as to enclose head 10. Thus whenever the cap 32 is pulled off the head portion 5, a slight suction is created in the space provided within the cap above the burner 12. This suction is sufiicient to draw a small amount of fuel through the orifice of the tank to help charge the cotton filling 23 already partially charged by fuel that has escaped through orifice 16. This action provides a very elfective way of drawing the fuel at the instant it is needed to enable the lighter unit to ignite in response to the sparks created by the sparking wheel 13, and to continue to burn for a fairly reasonable period of time without further charging. It should be noted that a lighter unit constructed in accordance with the preferred embodiment can provide enough of a fuel supply in the tank to enable the lighter to be charged and ignited in the above described manner on the order of a thousand or more times, thus enabling the use of the lighter unit to compete costwise with conventional matches, for example. After the lighter unit has used up all of its fuel in this manner, the lighter unit is thrown away, having served its useful purpose.

It should be clearly understood that the amount of fuel drawn through the orifice 16 by the suction created upon removal of the tightly fitted cap 32 can be controlled by the location and height of the land 7 provided on the housing portion 5 of the body 2. When the cap 32 is pulled oif the housing portion 5, the vacuum created above the burner 12 depends on the distance the inner wall of the cap 32 remains in tight sliding engagement with the land 7. The nearer the land is positioned to the upper end of the housing portion 5, the longer the suction is effective. It has been found that preferably the land 7 should be located near the lower end of the housing portion 5 and should be of such a size that the cap 32 maintains a tight fit thereof only for a short movement so as to limit the fuel drawn by the effective suction action.

As previously mentioned, the lighter unit when initially assembled at the factory is made self-serviceable including all the fuel it will ever need. Furthermore, the cap on the body is substantially airtight and is very effective in preventing fuel loss under normal use conditions. However, it is sometimes desirable to store a lighter unit for a long period of time before it is used, and to assure that the unit is kept airtight so that the fuel cannot escape, the present invention provides a sealing band 33 as shown in FIG. 4 which can be heat sealed onto the lighter unit at the time of assembly at the factory to completely seal the cap 32 to the body 2 to ensure permanent storage capability. This band 33 is provided with a pull-off tab 34 for easy removal. The band is preferably made of its same plastic material that the body 2 and cap 32 is made of. It is believed that such a sealed lighter unit can be stored indefinitely without loss of fuel from the tank or interaction of the fuel with the plastic body such that the unit will work reliably when opened up for use by removal of the band 33 by tab 34, even after an extended period of storage in adverse climatic environments. It should be clear, however, that even after removal of the band 33, the tight fitting cap on the upper portion of the body provides a substantially airtight enclosure for the burner and ignition means as well as the fuel tank of the lighter unit. Thus after the lighter unit is once used and the cap is replaced thereon, the lighter unit is still capable of withstanding all kinds of weather conditions and can even be submerged in water, for example, and still operate reliably.

As the fuel is gradually depleted during the time the lighter unit is being actively used the reliability of the lighter unit is not affected. In fact, the lighter continues to be useful until all the fuel in the tank is used up. It can be appreciated, however, that it is very desirable to know how much fuel is left in a particular lighter unit so as to have some indication of how much longer it will operate. Normally naphtha-like lighter fluid is colorless and is not easily detected in the plastic tank. It has therefore been found very desirable to color the fuel before placing it in the tank so that its presence can be detected through the translucent walls of the plastic tank.

While the lighter unit construction shown and described herein is admirably adapted to fulfill the objects and features of advantages previously enumerated as desirable, it is to be understood that the invention is not to be limited to the specific features shown and described but that the means and construction herein disclosed are susceptible of modification in form, proportion, and arrangement of parts without departing from the principle involved or sacrificing any of its advantages, and the invention is therefore claimed in embodiments of various forms all coming within the scope of the claims which follow.

What is claimed is:

1. A disposable lighter unit comprising: a plastic body having a fuel tank formed on the main lower portion thereof and a housing on the upper portion thereof; a supply of liquid fuel in said fuel tank with a space in the top of the tank for storing a vapor form of the fuel; a burner and an ignition means; a metallic head secured on the upper end of said housing for supporting said burner and said ignition means; a passageway in said housing interconnecting the burner in said head with an orifice provided in the top of said fuel tank; a filling of absorbent material in said passageway for enabling fuel passing through said orifice to be fed by capillary action to the burner; and a removable cap provided with an engaging fit on the housing portion of said body so as to provide a substantially airtight enclosure for the burner and ignition means supported on said head, said cap being effective upon being pulled off of the housing portion to create a suction about said burner to thereby draw fuel from the tank through the orifice into said passageway.

2. Apparatus in accordance with claim 1 wherein said housing portion is provided with a short ring-like bearing surface on which the inner wall of said cap has a tight sliding engagement to provide said substantially airtight enclosure, and wherein the location of said ring-like bearing surface on said housing portion controls the amount of suction effective to draw fuel from said tank through said orifice when said cap is removed from said body.

3. Apparatus in accordance with claim 1 wherein said burner comprises a loop formed of a Woven strand of cotton and asbestos pulled through an opening on the top of said head.

4. Apparatus in accordance with claim 1 wherein said orifice is on the order of .015 of an inch in diameter.

5. Apparatus in accordance with claim 4 wherein the inside wall of the tank surrounding said orifice is formed with a concave curvature.

6. Apparatus in accordance with claim 1 wherein said body and said cap is a plastic molding formed of polyethylene, and wherein said head is formed of a one-piece die metal casting.

7. A disposable lighter unit comprising: a plastic body having a fuel tank formed on the main lower portion thereof and a housing on the upper portion thereof; a supply of liquid fuel in said fuel tank with a space in the top of the tank for storing a vapor form of the fuel; said housing provided with a passageway extending therethrough and connected to an orifice located on the top of said tank and further provided with a cylindrical bore adjacent said passageway; a filling of cotton in said passageway and a spring urged flint positioned in said cylindrical bore; a cup-shaped metallic head, said head provided with a first and second tubular opening; a burner in the form of a loop including a woven strand of asbestos pulled through said first tubular opening and a sparking wheel mounted above said second tubular opening; said head securely fitting over the end of said housing portion with the burner in said first tubular opening mating with said passageway and with said second tubular opening mating with said spring-urged flint positioned in said cylindrical bore; and a removable plastic cap having a close fit over the housing portion of said body so as to provide a substantially airtight enclosure for the burner and sparking wheel supported on said head, said cap being effective upon being pulled off the housing portion of said body to create a suction about said burner to thereby draw fuel from the tank through said orifice into said passageway.

References Cited UNITED STATES PATENTS 1,748,323 2/1930 Aronson 431-142 2,503,640 4/1950 Speck 431-146 2,529,094 11/1950 Miller 431-149 2,784,581 3/1957 Quandt 431-301 3,092,988 6/1963 Meyers 431150 FOREIGN PATENTS 81,661 7/1919 Switzerland.

EDWARD J. MICHAEL, Primary Examiner 

